ODrive not Powering up - Short on 5V Rail

Support
1

Hey there,

Yesterday I connected an ODrive 3.6 56V for the first time.
Power comes from a Bench Power Supply which is isolated from mains PE set to 30V and 2A max.
No motor or Encoder connected, only the brake resistor was already attached.
Usb Connection to my Macbook running odrivetool.
When I turned on the PSU odrivetool briefly showed a successful connection, but disconnected again while I checked the next steps in the ‘Getting Started’ guide. So I can’t say how long it was alive.

After this it was not possible to reconnect and the power LED does not come on.
My PSU goes into current limitation (1.14V when set to a limit of 2A) instantly.

I checked the board if I can find any visibly damaged chips but could not find anything suspicious. Except that the M0 DRV is the only chip that get’s warm, so I assume that the voltage regulator is struggling to supply something. So i checked if the 3V3 or 5V lines have a short. And indeed my multimeter shows conductivity between a 5V pin and GND.

Symptoms are similar to the ones described here: ODrive died without any sparks (DC+ and DC- are shorted now)
I also see a short with my (cheap) multimeter between DC+ and DC-

Any ideas on what the cause could be and potential solutions?

Best regards,
Sebastian

1 Like
2

Hmm… It can happen that the 3.3v regulator fails short, pulling the 5V rail down. I would try to replace that chip.

The cause, I’m not sure in your case. Doesn’t sound like you did anything wrong. Do you have a thermal camera? if so, you might be able to see other short circuits.

3

Then I’ll order a chip for replacement and see if it fixes the problem.

Ok that’s bad and good. :grinning_face_with_smiling_eyes:
I unfortunately don’t have access to a thermal camera.

I have two additional ODrives for my project and I will try them out once I am back in the office somewhen this week and see if they work. As an additional precaution I will order a USB isolator, but I don’t think that this makes a difference with my setup, but it doesn’t hurt either. Or am I wrong in this assumption?

In the end the ODrives will be controlled via CAN anyway.

4

It certainly won’t hurt.